42/24-10 EN Rev. 9 Appendix 3: ZO23 Trace Oxygen Analyzer Module A-3-3
Test Gases
Reference point
(= electrical zero):
Clean ambient air; its oxygen concentration is established
from the value for dry air and the factor for consideration of
the water vapor content
Example:
Water vapor content at 25 °C and 50 % relative humidity
= 1.56 % Vol. O
2
⇒ Factor = (100 % – 1.56 %) / 100 % = 0.984
O
2
concentration = 20.93 % Vol. O
2
× 0.984 = 20.6 % Vol. O
2
Test Gases
End-point: Test gas with oxygen concentration in the smallest measuring
range (e.g. 2 ppm O
2
in N
2
)
Note The pressure conditions at reference point and end point must be identical!
Connection Diagram
Figure A-3-1
Connection Diagram
12
7
8
1 Sample gas inlet (3 mm Swagelok
®
)
2 Sample gas outlet (1/8 NPT female thread for
commercially available adapter, e.g. Swagelok
®
)
7 Housing purge gas inlet
1)
8 Housing purge gas outlet
1)
1) only in IP54 version